PIR Sensor False Triggers from Plasma TVs or Large Displays

Introduction

Large televisions, particularly older plasma screens, can emit significant infrared radiation and electrical noise that interferes with PIR sensors.

How Displays Cause Interference

Plasma TVs (Worst Offenders)

Plasma displays generate significant heat and emit IR. The picture content changes rapidly, creating varying IR patterns that can mimic motion.

Large LED/LCD TVs

LED-backlit LCDs generate less heat, but the backlight can still produce IR.

Electrical Noise

All large displays have switching power supplies that can generate EMI.

Symptoms

• False triggers only when TV is on.
• Triggers correlated with scene changes or bright scenes.
• Sensor located near TV in home theater setup.

Solutions

• Relocate sensor away from the TV (1-2 meters).
• Mount sensor on side wall or ceiling, not facing the TV.
• Add physical barrier between sensor and TV.
• Reduce sensitivity.
• Use a sensor with better IR filter.

Conclusion

Large displays can interfere with PIR sensors. Relocation is the most effective solution.